Electric drive vehicle with low speed creep

ABSTRACT

Systems and methods to control the vehicle speed of a vehicle includes a motor and a controller coupled to the motor. The controller is structured to: determine that a speed of a vehicle is at or above a predetermined speed limit; activate a motor speed governor responsive to an input received by the controller, wherein the motor speed governor is structured to control a vehicle speed; and adjust an output torque based on the vehicle speed being at or above the predetermined speed limit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/470,442, filed Jun. 17, 2019, which is a 35 U.S.C. § 371 nationalstage filing of PCT/US2017/067554, filed Dec. 20, 2017, which claims thebenefit of and priority to U.S. Provisional Application No. 62/440,098,filed Dec. 29, 2016, which are hereby incorporated by reference in itsentirety.

TECHNICAL FIELD

The present application relates generally to the field of vehicle speedsystems. More particularly, the present application relates to systemsand methods for controlling the vehicle speed for direct drive electricvehicles.

BACKGROUND

In general, a torque converter allows a vehicle equipped with anAutomatic Transmission (AT) to seamlessly edge forward (or backward)from a full stop with little or no effort from the operator. Unlike theAT, a vehicle equipped with an Automated Manual Transmission (AMT) or aManual Transmission (MT) is engaged with a clutch. When the engine of avehicle that has an AMT or a MT is operating at its minimum idle speed,such vehicles experience clutch engagement issues that leave the vehiclemoving faster than desired. To operate the vehicle at a slower desiredspeed requires the operator to allow the clutch to slip which decreasesthe life of the clutch. The engine may also be lugged back to sub-idlespeeds to operate the vehicle at a slower desired speed, however, speedcontrol may not be stable or the engine may stall.

A direct-drive electric vehicle is powered by the engagement of a motorand a battery without the need of an engine or transmission. The motorreceives power from the energy stored in the direct-drive vehiclebattery. In general, direct-drive electric vehicles are an efficientalternative to a vehicle, such as an AT, AMT, or MT, that utilizesgasoline or diesel power. Unlike the AMT and the MT, a direct-driveelectric vehicle does not have a combined driveline clutch and minimumpower plant speed that establishes a minimum vehicle speed. However,operating a direct-drive electric vehicle at very low speeds and loadsis extremely inefficient. In a parking or other low speed maneuveringsituation, it may be desirable to have precise control over thedriveline torque.

Therefore, there exists a need to maneuver a direct-drive electricvehicle at low speeds that allow the vehicle to automatically movegradually when the brake is released. Having the ability to movegradually, for example to inch forward or backward when the brake pedalis released, advantageously provides the ability to drive and maneuverdirect- drive electric vehicles with precision at low speeds.

SUMMARY

One implementation relates to a system. The system includes a motor anda brake mechanism structured to receive an indication of a desiredchange in vehicle speed. The system further includes a controllercommunicatively coupled to the motor and the brake mechanism. Thecontroller is structured to receive the indication of the desired changein the vehicle speed, activate a motor speed governor responsive to thebrake mechanism being in a released state, and adjust an output torqueresponsive to the vehicle speed, wherein as a load corresponding to themotor increases the vehicle speed decreases.

These and other features of the implementations described herein,together with the organization and manner of operation thereof, willbecome apparent from the following detailed description when taken inconjunction with the accompanying drawings, wherein like elements havelike numerals throughout the several drawings described below.

BRIEF DESCRIPTION OF THE DRAWINGS

The details of one or more implementations are set forth in theaccompanying drawings and the description below. Other features,aspects, and advantages of the disclosure will become apparent from thedescription, the drawings, and the claims, in which:

FIG. 1 is a schematic block diagram of an example vehicle having anexample brake mechanism according to an example embodiment;

FIG. 2 is a schematic block diagram of a controller included in thevehicle of FIG. 1 according to an example embodiment;

FIG. 3 is a diagram of the vehicle speed set to zero miles per houraccording to some embodiments;

FIG. 4 is a diagram of the vehicle speed and output torque in anon-reverse direction according to some embodiments;

FIG. 5 is a diagram of the vehicle speed and output torque in a reversedirection according to some embodiments;

FIG. 6 is a diagram of the vehicle speed and output torque in a reversedirection according to some embodiments;

FIG. 7 is a diagram of the vehicle speed and output torque in anon-reverse direction according to some embodiments;

FIG. 8 is a diagram of the vehicle speed and output torque in a reversedirection according to some embodiments; and

FIG. 9 is a schematic flow diagram of an example method of controllingthe vehicle speed of a vehicle.

It will be recognized that some or all of the figures are schematicrepresentations for purposes of illustration. The figures are providedfor the purpose of illustrating one or more implementations with theexplicit understanding that they will not be used to limit the scope orthe meaning of the claims.

DETAILED DESCRIPTION

Below is a detailed description of various concepts related to, andimplementations of, methods, apparatuses, and systems for controllingthe vehicle speed of a vehicle. The various concepts introduced aboveand discussed in greater detail below may be implemented in any ofnumerous ways, as the described concepts are not limited to anyparticular manner of implementation. Examples of specificimplementations and applications are provided primarily for illustrativepurposes.

Referring to the Figures generally, the various embodiments disclosedherein relate to a system and method for controlling the vehicle speed(e.g., a low speed, such as the speed at which a vehicle creeps during amaneuver) of a vehicle (e.g., a direct-drive electric vehicle or hybridvehicle). According to the present disclosure, a controller receives,via a brake mechanism of a direct-drive electric vehicle, an indicationof a desired change in vehicle speed (e.g., whether the vehicle operatordesires for a braking action to be applied), activates a motor speedgovernor structured to control the vehicle speed responsive to the brakemechanism in a released state, and adjusts, via the motor speedgovernor, an output torque responsive to the vehicle speed. As a loadcorresponding to the motor increases the vehicle speed decreases.

FIG. 1 depicts a schematic block diagram of an example vehicle 100according to an example embodiment. The vehicle 100 may be a vehicle,such as a direct-drive electric vehicle or a hybrid vehicle, powered byor otherwise operable via a battery, generator (e.g., a power generator,generator plant, electric power strip, on-board rechargeable electricitystorage system, etc.), a motor (e.g., an electric motor, traction motor,etc.), etc. The vehicle 100 may be operable in at least one of a reversedirection (e.g., a backward direction) and a non-reverse direction(e.g., a forward direction, angular direction, etc.). The vehicle 100may be an on-road or off-road vehicle including, but not limited to,cars, trucks, ships, boats, vans, airplanes, spacecraft, or any othertype of vehicle.

The vehicle 100 is shown to generally include a controller 150communicably and operatively coupled to a brake mechanism 120 (e.g., abrake, braking system, or any other device configured to prevent orreduce motion by slowing or stopping components (e.g., a wheel, axle,pedal, etc. of a vehicle), powertrain system 110, an operatorinput/output (I/O) device 135, and one or more additional vehiclesubsystems 140. It should be understood that the vehicle 100 may includeadditional, less, and/or different components/systems than depicted inFIG. 1, such that the principles, methods, systems, apparatuses,processes, and the like of the present disclosure are intended to beapplicable with any other vehicle configuration. It should also beunderstood that the principles of the present disclosure should not beinterpreted to be limited to on-highway vehicles; rather, the presentdisclosure contemplates that the principles may also be applied to avariety of other applications including, but not limited to, off-highwayconstruction equipment, mining equipment, marine equipment, locomotiveequipment, etc.

The powertrain system 110 facilitates power transfer from the motor 113and/or the battery 132 to power the vehicle 100. In an exampleembodiment, the vehicle (e.g., a direct-drive electric vehicle and/or ahybrid vehicle) may be operable via a powertrain system 110 whichincludes a motor 113 operably coupled to a battery 132 and charge system134, where the motor 113 transfers power to the final drive (shown aswheels 115) to propel the vehicle 100. As depicted, the powertrainsystem 110 includes various components that may be included in adirect-drive electric vehicle and/or a hybrid vehicle, such as forexample, an engine 111 operably coupled to a transmission 112, a motor113, and a differential 114, where the differential 114 transfers poweroutput from the engine 111 to the final drive (shown as wheels 115) topropel the vehicle 100. As a brief overview and in this configuration,the controller 150 of the vehicle 100 (e.g., an electric vehicle)provides electricity to the motor 113 (e.g., an electric motor) inresponse to input received by the controller 150 from the acceleratorpedal 122, charge system 134 (e.g., a battery charging system,rechargeable battery, etc.), etc. In some embodiments, the electricityprovided to power the motor 113 may be provided by an onboardgasoline-engine generator, a hydrogen fuel cell, etc.

In some embodiments, the vehicle 100 may also include the engine 111which may be structured as an internal combustion engine that receives achemical energy input (e.g., a fuel such as natural gas, gasoline,ethanol, or diesel) from the fuel delivery system 130, and combusts thefuel to generate mechanical energy, in the form of a rotatingcrankshaft. The transmission 112 receives the rotating crankshaft andmanipulates the speed of the crankshaft (e.g., the engine speed, whichis usually expressed in revolutions-per-minute (RPM)) to effect adesired drive shaft speed. A rotating drive shaft may be received by adifferential 114, which provides the rotation energy from the driveshaft to the final drive 115. The final drive 115 then propels or movesthe vehicle 100. Further, the drive shaft may be structured as aone-piece, two-piece, and/or a slip-in-tube driveshaft based on theapplication.

In some examples, the vehicle 100 may include the transmission 112. Thetransmission 112 may be structured as any type of transmission, such asa continuous variable transmission, a manual transmission, an automatictransmission, an automatic-manual transmission, a dual clutchtransmission, etc. Accordingly, as transmissions vary from geared tocontinuous configurations (e.g., continuous variable transmission), thetransmission can include a variety of settings (e.g., gears, for ageared transmission) that affect different output speeds based on theengine speed. Like the engine 111 and the transmission 112, motor 113,differential 114, and final drive 115 may be structured in anyconfiguration dependent on the application (e.g., the final drive 115 isstructured as wheels in an automotive application and a propeller in anairplane application).

The vehicle 100 may include a throttle system (e.g., a throttle systemincluding an intake manifold throttle) depending on the engine systemutilized. The throttle system generally includes a throttle valve (e.g.,a ball valve, a butterfly valve, a globe valve, or a plug valve), whichin certain embodiments is operatively and communicably coupled to anaccelerator pedal 122 and/or one or more sensors 123. The throttle valveis structured to selectively control the amount of intake air providedto the engine 111. Because the type of engine 111 may vary fromapplication-to-application, the type of throttle valve may also varywith all such possibilities and configurations falling within the spiritand scope of the present disclosure. The term “throttle system” as usedherein should be understood broadly, and may refer to any air managementsystem, including without limitation an intake throttle, an exhaustthrottle, and/or manipulations of an air handling device such as aturbocharger (e.g. a wastegate turbocharger and/or a variable geometryturbocharger). The throttle system may additionally or alternatively beactive during stoichiometric-like operations of the engine, and inactiveor less active during lean burn-like operations of the engine. Thethrottle system may be manipulated, in certain embodiments, in responseto the engine speed, load, and/or substitution rate, independentlyand/or in conjunction with a signal from the accelerator pedal 122.

The accelerator pedal 122 may be structured as any type of torque and/orspeed request device included with a system (e.g., a floor-based pedal,an acceleration lever, etc.). Further, the sensors 123 may include anytype of sensors included with the brake mechanism 120, accelerator pedal122, or any other component and/or system included in the powertrainsystem 110 of a vehicle. For example, the sensors 123 may include anaccelerator pedal position sensor that acquires data indicative of adepression amount of the pedal (e.g., a potentiometer), a brakemechanism sensor that acquires data indicative of a depression amount ofthe brake mechanism 120 (e.g., a brake, brake pedal, etc.), a fueltemperature sensor, a charge air temperature sensor, a coolanttemperature and pressure sensor, an ambient air temperature and pressuresensor, a fuel pressure sensor, an injection pump speed sensor, and thelike.

As depicted, the vehicle 100 includes the operator I/O device 135. Theoperator I/O device 135 enables an operator of the vehicle tocommunicate with the vehicle 100 and the controller 150. Analogously,the I/O device 135 enables the vehicle or controller 150 to communicatewith the operator. For example, the operator I/O device 135 may include,but is not limited, an interactive display (e.g., a touchscreen, etc.)having one or more buttons/input devices, haptic feedback devices, anaccelerator pedal, a brake pedal, a shifter for the transmission, acruise control input setting, a navigation input setting, etc. Via theI/O device 135, the controller 150 can also providecommands/instructions/information to the operator (or a passenger).

As also shown, the vehicle 100 includes one or more vehicle subsystems140. The various vehicle subsystems 140 may generally include one ormore sensors (e.g., a speed sensor, torque sensor, ambient pressuresensor, temperature sensor, etc.), as well as any subsystem that may beincluded with a vehicle. Accordingly, in an embodiment including ahybrid vehicle, the subsystems 140 may also include an exhaustaftertreatment system structured to reduce diesel exhaust emissions,such as a selective catalytic reduction catalyst, a diesel oxidationcatalyst (DOC), a diesel particulate filter (DPF), a diesel exhaustfluid doser with a supply of diesel exhaust fluid, and a plurality ofsensors for monitoring the exhaust aftertreatment system (e.g., a NOxsensor).

The controller 150 is communicably and operatively coupled to thepowertrain system 110, brake mechanism 120, accelerator pedal 122, theoperator I/O device 135, and the one or more vehicle subsystems 140.Communication between and among the components may be via any number ofwired or wireless connections (e.g., any standard under IEEE 802, etc.).For example, a wired connection may include a serial cable, a fiberoptic cable, an SAE J1939 bus, a CATS cable, or any other form of wiredconnection. In comparison, a wireless connection may include theInternet, Wi-Fi, Bluetooth, Zigbee, cellular, radio, etc. In oneembodiment, a controller area network (CAN) bus including any number ofwired and wireless connections provides the exchange of signals,information, and/or data. Because the controller 150 is communicablycoupled to the systems and components in the vehicle 100 (e.g., adirect-drive electric vehicle, etc.) of FIG. 1, the controller 150 isstructured to receive data (e.g., instructions, commands, signals,values, etc.) from one or more of the components shown in FIG. 1.

It should also be understood that other or additional operatingparameters to control the vehicle speed may be used. For example,additional parameters may include motor speed, battery characteristics(e.g., battery voltage), characteristics of the fuel delivery system 130(e.g., timing, quantity, rate, etc. of a hybrid vehicle),characteristics regarding the brake position/operation and so on.

The controller 150 includes a speed management circuit 232 as describedherein with reference to FIG. 2. The speed management circuit 232 may becommunicatively coupled to the powertrain system 110. Further, as thecomponents of FIG. 1 are shown to be embodied in a vehicle 100 (e.g., adirect-drive electric vehicle), the controller 150 may be structured as,include, or be communicably and operatively coupled to at least one of amotor controller, powertrain system controller, etc. The function andstructure of the controller 150 is described herein with reference toFIG. 2.

FIG. 2 is a schematic block diagram of a controller 150 included in avehicle (e.g., the vehicle 100) according to an example embodiment. Inthe present embodiment, the controller 150 includes a processor 220, anda memory 230 or other computer readable medium. It should be understoodthat the controller 150 of FIG. 2 depicts only one embodiment of thecontroller 150, and any other controller capable of performing theoperations described herein can be used. In some embodiments and asalluded to above, the controller 150 may take the form of at least oneof a motor controller or a powertrain system controller.

The processor 220 can include a microprocessor, programmable logiccontroller (PLC) chip, an ASIC chip, or any other suitable processor.The processor 220 is in communication with the memory 230 and structuredto execute instructions, algorithms, commands or otherwise programsstored in the memory 230.

The memory 230 includes any of the memory and/or storage componentsdiscussed herein. For example, the memory 230 may include RAM and/orcache of the processor 220. The memory 230 may also include one or morestorage devices (e.g., hard drives, flash drives, computer readablemedia, etc.) either local or remote to the controller 150. The memory230 is structured to store look up tables, algorithms, or instructions.

The speed management circuit 232 may be structured to receive, via abrake mechanism 120 of a vehicle 100 (e.g., a direct-drive electricvehicle), an indication of a desired change in vehicle speed. In someembodiments, the brake mechanism 120 may take the form of a brake, brakepedal, brake system, etc. The brake mechanism 120 may be structured tomove or is otherwise operable between a depressed state and a releasedstate. One or more sensors 123 (e.g., speed sensors) read, monitor, orotherwise record the speed of the rotation of the wheels 115 whichprovide an indication of a change in the vehicle speed. The vehiclespeed may increase, decrease, or remain the same.

When the brake mechanism 120 is in the depressed state (e.g., the brakemechanism 120 is pressed or otherwise pushed), a force is applied suchthat the vehicle speed is adjusted (e.g., decreases) or the vehicle 100is slowed to a stop. The vehicle speed may be adjusted in proportion toan application of the brake mechanism. For example, in the depressedstate, the brake mechanism 120 applies a force which may causeengagement of a switch and/or friction between components of a brakesystem (e.g., the brake pads, brake rotors, etc.) such that theindication of the desired change in vehicle speed, for example a reducedvehicle speed, is read by the sensors 123. In some examples, theapplication of a force by the brake mechanism 120 in the depressed statemay cause the motor 113 to enter a power generation state (e.g., themotor generates electricity which is provided to the battery 132). Inthe power generation state, the motor 113 causes the wheels 115 to slowwhich reduces the vehicle speed. In turn, the indication of the changein the vehicle speed is received by the speed management circuit 232.

Alternatively or additionally, the brake mechanism 120 may be in areleased state. The brake mechanism 120 may enter the released statewhen the brake mechanism is released or when a force is no longerapplied to the brake mechanism 120. For example, the brake mechanism 120(e.g., the brake pedal) enters the released state when the brake pedalis released by the operator of the vehicle 100. In turn, the vehicle 100begins to move or otherwise accelerate to a vehicle speed (e.g., a lowspeed) in a direction determined by a gear selection system (e.g., in areverse direction or non-reverse direction).

The speed management circuit 232 may be structured to activate a motorspeed governor (e.g., a speed limiter device) responsive to the brakemechanism 120 in the released state. As used herein, the term “motorspeed governor” may be used to refer to a device, system, etc.structured to manage (e.g., control, limit, set, etc.) vehicle speedand/or output torque. In some embodiments, the motor speed governor maytake the form of a proportional governor (e.g., a droop governor). Themotor speed governor may be activated responsive to the brake mechanism120 moving from a depressed state to a released state. In someembodiments, the speed management circuit 232 may be structured todetermine whether the brake mechanism is in the released state.Alternatively or additionally, the speed management circuit 232 may bestructured to activate the motor speed governor (e.g., a speed limiterdevice) responsive to an input received via the input/output device 135.For example, the activation of the motor speed governor may beassociated with a gear selectable by an operator. The gear may beselectable via a gear selection system such as, but not limited to, agear stick, gear shift, gear lever, an onboard diagnostic system (OBD),a display associated with the vehicle, vehicle dash, information system,etc. The gear once selected may cause the activation of the motor speedgovernor when desired by the operator of the vehicle 100.

The motor speed governor is operable between a first speed and a secondspeed. The first speed may include a speed rate of zero miles per hour(mph). The first speed may include a speed rate greater or less thanzero miles per hour. The second speed may include a calibratable speed.The calibratable speed may correspond to a low speed between 0 and 2.5miles per hour. In some embodiments, the motor speed governor may limitthe vehicle speed such that when the vehicle speed increases orotherwise reaches a predetermined speed limit the vehicle speed may beprevented from increasing further. In this regard, one or more sensors123 may detect the vehicle speed. The vehicle speed may be received bythe motor speed governor. The motor speed governor may determine whetherthe vehicle speed has reached the predetermined speed limit. If thevehicle speed of, for example a direct-drive electric vehicle, reachesthe predetermined speed limit, the speed management circuit 232 and/orthe motor speed governor may prevent the direct-drive electric vehicleand/or hybrid vehicle from exceeding the predetermined speed. If thevehicle speed of, for example a hybrid vehicle, reaches or exceeds thepredetermined speed, the speed management circuit 232 may limit the flowof air and/or fuel to the engine 111 that causes combustion to, thereby,limit the vehicle speed.

When the brake mechanism 120 is in the depressed state, for example, thebrake pedal may be continuously applied which may decrease the vehiclespeed causing the vehicle speed to go to zero miles per hour. When thebrake mechanism 120 is released (e.g., moves from the depressed state tothe released state), the motor speed governor may gradually (e.g.,slowly) ramp up or otherwise increase the vehicle speed from the firstspeed to a calibratable speed (e.g., the second speed such as a nominalspeed between 0 and 2.5 miles per hour). Alternatively or additionally,if the brake mechanism 120 and the accelerator pedal 122 are released,the motor speed governor gradually (e.g., slowly) ramps up or otherwiseincreases from the first speed to the calibratable speed (e.g., thesecond speed). Although the above example includes a nominal speedbetween 0 and 2.5 miles per hour, the example is understood not to limitthe scope of vehicle speeds that may be achieved in various embodiments.

The controller 150 further includes the response management circuit 234.The response management circuit 234 may be structured to adjust, via themotor speed governor, an output torque responsive to the vehicle speed.The term “output torque” as used herein may refer to the amount of forcethe motor outputs or otherwise provides. The output torque may beincreased responsive to an adjustment of the vehicle speed. The motorspeed governor senses the decrease in the vehicle speed (e.g., thedecrease in revolutions-per-minute (RPM)) due to the application of thebrake mechanism 120 that works against the power of the motor 113. Inturn, the motor speed governor increases the output torque to counteractthe decrease in the vehicle speed and/or to maintain the vehicle speed.Further description of the motor 113 and the increased output torque isdescribed herein below with reference to FIGS. 3-8.

The powertrain system 110 eventually reaches an equilibrium at anincreased load and a lower vehicle speed as the output torque increaseswhen the brake mechanism 120 is continuously applied. For example, whena load corresponding to the motor 113 increases, the vehicle speeddecreases (e.g., the RPM decreases). The load may increase due to thevehicle 100 being on an inclined road such that an increased outputtorque is required to maintain speed. The load may increase because theoperator is applying a variable amount of force to the brake mechanism120 such that the motor 113 increases the output torque to overcome thedrag of the brakes. In some embodiments, the vehicle speed is adjustedin proportion to the load increase. Accordingly, the motor speedgovernor may include the droop governor as described above such that asthe load increases, the vehicle speed decreases proportionally.Alternatively or additionally, the increased output torque decreases thevehicle speed according to a governed speed droop line (e.g., a speeddroop line slope) as described in FIGS. 4-8.

In some embodiments, the response management circuit 234 may bestructured to generate a command (e.g., a code) structured to cause themotor speed governor to control the vehicle speed between the firstspeed and the second speed. In some embodiments, the response managementcircuit 234 may be structured to generate a plurality of commands. Inthis regard, the command communicates operating parameters to thepowertrain system 110 to actuate various components, circuits, or leversof the powertrain system 110 to cause the vehicle 100 to move orotherwise operate between the first speed and the second speed (e.g., anominal speed between 0 and 2.5 miles per hour) such that the vehicle100 automatically moves (e.g., gradually moves forward or backward,gradually reduces speed to zero, inches forward or backward, edgesforward or backward, creeps, etc.) in a reverse direction and/or anon-reverse direction.

In further embodiments, the response management circuit 234 may bestructured to deactivate the motor speed governor responsive to at leastone of the vehicle speed comprising a speed rate of zero miles per houror receiving an indication of a desired change in vehicle acceleration.For example, if the application of the brake mechanism 120 causes thevehicle speed to decrease to zero miles per hour, the responsemanagement circuit 234 may deactivate the motor speed governor. If theapplication of the accelerator pedal 122 indicates a desired change invehicle acceleration (e.g., depressing the accelerator pedal 122 causesthe vehicle speed to increase), the response management circuit 234 maydeactivate the motor speed governor. The response management circuit 234may be structured to deactivate the motor speed governor responsive toat least one of the vehicle speed comprising a speed rate of zero milesper hour or receiving an indication of a desired change in vehicleacceleration.

FIGS. 3-8 illustrate the control of the vehicle speed according tovarious embodiments. As illustrated in FIG. 3 at A, initially thevehicle speed is set to zero miles per hour. In this example, the brakemechanism (e.g., the brake pedal) may be applied which, thereby, causesthe brake mechanism to operate in a depressed state as described hereinabove. In FIG. 4 which illustrates the vehicle speed and output torquein a non-reverse direction, the accelerator pedal is not depressed andthe output torque is set to zero. The vehicle speed increases to acalibratable speed rate of, for example, 0.5 miles per hour per second.When the vehicle speed increases or otherwise reaches a second speed of2.5 miles per hour, the vehicle speed, which is controlled via the motorspeed governor, may stop increasing. As illustrated at B when thevehicle speed increases, the motor speed governor increases the outputtorque such that the vehicle speed behaves according to the governedspeed droop line. In turn, the increased output torque which counteractsthe vehicle speed increase causes the vehicle speed to decrease.

FIGS. 5-6 illustrate the vehicle speed and output torque in a reversedirection according to some embodiments. In this example, the brakemechanism may not be applied such that the brake mechanism operates in areleased state as described herein above. The motor speed governor isactivated with a vehicle speed set to zero miles per hour at C. Thevehicle speed decreases to a calibratable rate of, for example, −0.5miles per hour per second due to the reversed direction of the vehicle.The vehicle speed, which is controlled via the motor speed governor,stops decreasing when the vehicle speed decreases or otherwise reaches asecond speed of −2.5 miles per hour as shown in FIG. 6 at D.

FIG. 7 illustrates the vehicle speed and output torque in a non-reversedirection. The brake mechanism may be applied which causes the brakemechanism to operate in a depressed state. The motor increases theoutput torque to maintain the vehicle speed against the increased forceapplied to the brake mechanism. As the output torque increases, thevehicle speed decreases proportionally along the governed speed droopline. The vehicle speed and load may reach equilibrium dependent on theapplication of the brakes mechanism by the operator at E. With enoughbraking force, the output torque may be increased to counter theapplication of the brake mechanism. The vehicle speed may decrease(e.g., droop) to zero miles per hour which deactivates the motor speedgovernor.

In the example embodiment of FIG. 8 which illustrates the vehicle speedand output torque in a reverse direction, the brake mechanism may beapplied to cause the brake mechanism to operate in a depressed state.The motor increases the output torque to maintain the vehicle speedagainst the application of the brake mechanism. As the output torqueincreases, the vehicle speed increases proportionally along the governedspeed droop line. The vehicle speed and load may reach equilibriumdependent on the application of force to the brakes mechanism by theoperator at F.

FIG. 9 is a flow diagram of an example process 900 for a controller tocontrol the vehicle speed of a vehicle (e.g., a direct-drive electricvehicle or hybrid vehicle) via the circuits described herein withreference to FIG. 2. At 902, the process 900 includes receiving, via abrake mechanism communicatively coupled to a motor of a vehicle, anindication of a desired change in vehicle speed. For example, anindication of a change in vehicle speed is received when a brakemechanism is applied such that the vehicle speed decreases or slows to astop.

At 904, a motor speed governor (e.g., a speed limiter device) structuredto control the vehicle speed may be activated by a controller. The motorspeed governor may be activated responsive to the brake mechanism movingfrom a depressed state to a released state. As the brake mechanism isreleased (e.g., moves from the depressed state to the released state),the motor speed governor may gradually (e.g., slowly) ramp up orotherwise increase the vehicle speed from a first speed to a secondspeed (e.g., a nominal speed between 0 and 2.5 miles per hour).

At 906, an output torque is adjusted by a controller responsive to thevehicle speed. As the brake mechanism is applied, the application of thebrake mechanism works against the power of the motor. In order tocounteract the application of the brake mechanism, the motor increasesthe output torque via the motor speed governor. When a loadcorresponding to the motor increases, the vehicle speed decreases. Inturn, the vehicle speed is adjusted in proportion to the load increasesuch that while operating between the first speed and the second speed,the vehicle 100 automatically moves gradually forward or backward,inches forward or backward, edges forward or backward, etc.

The schematic flow chart diagrams and method schematic diagramsdescribed above are generally set forth as logical flow chart diagrams.As such, the depicted order and labeled steps are indicative ofrepresentative embodiments. Other steps, orderings and methods may beconceived that are equivalent in function, logic, or effect to one ormore steps, or portions thereof, of the methods illustrated in theschematic diagrams.

Additionally, the format and symbols employed are provided to explainthe logical steps of the schematic diagrams and are understood not tolimit the scope of the methods illustrated by the diagrams. Althoughvarious arrow types and line types may be employed in the schematicdiagrams, they are understood not to limit the scope of thecorresponding methods. Indeed, some arrows or other connectors may beused to indicate only the logical flow of a method. For instance, anarrow may indicate a waiting or monitoring period of unspecifiedduration between enumerated steps of a depicted method. Additionally,the order in which a particular method occurs may or may not strictlyadhere to the order of the corresponding steps shown. It will also benoted that each block of the block diagrams and/or flowchart diagrams,and combinations of blocks in the block diagrams and/or flowchartdiagrams, can be implemented by special purpose hardware-based systemsthat perform the specified functions or acts, or combinations of specialpurpose hardware and program code.

Many of the functional units described in this specification have beenlabeled as circuits, in order to more particularly emphasize theirimplementation independence. For example, a circuit may be implementedas a hardware circuit comprising custom VLSI circuits or gate arrays,off-the-shelf semiconductors such as logic chips, transistors, or otherdiscrete components. A circuit may also be implemented in programmablehardware devices such as field programmable gate arrays, programmablearray logic, programmable logic devices or the like.

Circuits may also be implemented in machine-readable medium forexecution by various types of processors. An identified circuit ofexecutable code may, for instance, comprise one or more physical orlogical blocks of computer instructions, which may, for instance, beorganized as an object, procedure, or function. Nevertheless, theexecutables of an identified circuit need not be physically locatedtogether, but may comprise disparate instructions stored in differentlocations which, when joined logically together, comprise the circuitand achieve the stated purpose for the circuit.

Indeed, a circuit of computer readable program code may be a singleinstruction, or many instructions, and may even be distributed overseveral different code segments, among different programs, and acrossseveral memory devices. Similarly, operational data may be identifiedand illustrated herein within circuits, and may be embodied in anysuitable form and organized within any suitable type of data structure.The operational data may be collected as a single data set, or may bedistributed over different locations including over different storagedevices, and may exist, at least partially, merely as electronic signalson a system or network. Where a circuit or portions of a circuit areimplemented in machine-readable medium (or computer-readable medium),the computer readable program code may be stored and/or propagated on inone or more computer readable medium(s).

The computer readable medium may be a tangible computer readable storagemedium storing the computer readable program code. The computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, holographic,micromechanical, or semiconductor system, apparatus, or device, or anysuitable combination of the foregoing.

More specific examples of the computer readable medium may include butare not limited to a portable computer diskette, a hard disk, a randomaccess memory (RAM), a read-only memory (ROM), an erasable programmableread-only memory (EPROM or Flash memory), a portable compact discread-only memory (CD-ROM), a digital versatile disc (DVD), an opticalstorage device, a magnetic storage device, a holographic storage medium,a micromechanical storage device, or any suitable combination of theforegoing. In the context of this document, a computer readable storagemedium may be any tangible medium that can contain, and/or storecomputer readable program code for use by and/or in connection with aninstruction execution system, apparatus, or device.

The computer readable medium may also be a computer readable signalmedium. A computer readable signal medium may include a propagated datasignal with computer readable program code embodied therein, forexample, in baseband or as part of a carrier wave. Such a propagatedsignal may take any of a variety of forms, including, but not limitedto, electrical, electro-magnetic, magnetic, optical, or any suitablecombination thereof. A computer readable signal medium may be anycomputer readable medium that is not a computer readable storage mediumand that can communicate, propagate, or transport computer readableprogram code for use by or in connection with an instruction executionsystem, apparatus, or device. Computer readable program code embodied ona computer readable signal medium may be transmitted using anyappropriate medium, including but not limited to wireless, wireline,optical fiber cable, Radio Frequency (RF), or the like, or any suitablecombination of the foregoing.

In one embodiment, the computer readable medium may comprise acombination of one or more computer readable storage mediums and one ormore computer readable signal mediums. For example, computer readableprogram code may be both propagated as an electro-magnetic signalthrough a fiber optic cable for execution by a processor and stored onRAM storage device for execution by the processor.

Computer readable program code for carrying out operations for aspectsof the present invention may be written in any combination of one ormore programming languages, including an object oriented programminglanguage such as Java, Smalltalk, C++ or the like and conventionalprocedural programming languages, such as the “C” programming languageor similar programming languages. The computer readable program code mayexecute entirely on the user's computer, partly on the user's computer,as a stand-alone computer-readable package, partly on the user'scomputer and partly on a remote computer or entirely on the remotecomputer or server. In the latter scenario, the remote computer may beconnected to the user's computer through any type of network, includinga local area network (LAN) or a wide area network (WAN), or theconnection may be made to an external computer (for example, through theInternet using an Internet Service Provider).

The program code may also be stored in a computer readable medium thatcan direct a computer, other programmable data processing apparatus, orother devices to function in a particular manner, such that theinstructions stored in the computer readable medium produce an articleof manufacture including instructions which implement the function/actspecified in the schematic flowchart diagrams and/or schematic blockdiagrams block or blocks.

Reference throughout this specification to “one embodiment,” “anembodiment,” or similar language means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment of the present invention. Thus,appearances of the phrases “in one embodiment,” “in an embodiment,” andsimilar language throughout this specification may, but do notnecessarily, all refer to the same embodiment.

Accordingly, the present disclosure may be embodied in other specificforms without departing from its spirit or essential characteristics.The described embodiments are to be considered in all respects only asillustrative and not restrictive. The scope of the disclosure is,therefore, indicated by the appended claims rather than by the foregoingdescription. All changes which come within the meaning and range ofequivalency of the claims are to be embraced within their scope. Noclaim element herein is to be construed under the provisions of 35U.S.C. § 112, sixth paragraph, unless the element is expressly recitedusing the phrase “means for.”

What is claimed is:
 1. A system, comprising: a motor; and a controller coupled to the motor, the controller structured to: determine that a speed of a vehicle is at or above a predetermined speed limit; activate a motor speed governor responsive to an input received by the controller, wherein the motor speed governor is structured to control a vehicle speed; and adjust an output torque based on the vehicle speed being at or above the predetermined speed limit.
 2. The system of claim 1, wherein the vehicle is a direct-drive electric vehicle or a hybrid vehicle.
 3. The system of claim 1, wherein the motor speed governor is operable between a first speed and a second speed, and wherein the first speed comprises a speed rate of zero miles per hour and the second speed comprises a calibratable speed.
 4. The system of claim 1, wherein the calibratable speed corresponds to a rate of speed between zero miles per hour and approximately 2.5 miles per hour
 5. The system of claim 1, wherein the adjustment of the output torque responsive to the input received by the controller comprises adjusting the output torque in proportion to a load on the motor.
 6. The system of claim 1, wherein the output torque is increased responsive to an adjustment of the vehicle speed.
 7. The system of claim 1, wherein the vehicle speed is adjusted based on an application of a brake mechanism.
 8. The system of claim 7, wherein the brake mechanism is movable between a depressed state and a released state.
 9. The system of claim 1, wherein the controller is further structured to deactivate the motor speed governor responsive to at least one of the vehicle speed having a rate of zero miles per hour or receiving an indication of the vehicle speed being below the predetermined speed limit.
 10. The system of claim 1, wherein the input includes a transmission setting of a transmission of the vehicle.
 11. A system comprising: at least one processing circuit comprising a processor coupled to a memory device storing instructions therein that, when executed by the processor, cause the processing circuit to: determine that a speed of a vehicle is at or above a predetermined speed limit; receive an input; activate a motor speed governor based on the input, wherein the motor speed governor is structured to control a vehicle speed; and adjust, via the motor speed governor, an output torque based on the vehicle speed being at or above the predetermined speed limit.
 12. The system of claim 11, wherein the motor speed governor is operable between a first speed and a second speed, and wherein the first speed comprises a speed rate of zero miles per hour and the second speed comprises a calibratable speed.
 13. The system of claim 12, wherein the adjustment of the output torque based on the input comprises adjusting the output torque in proportion to a load on a motor.
 14. The system of claim 11, wherein the instructions, when executed by the processor, further cause the processing circuit to deactivate the motor speed governor responsive to at least one of the vehicle speed comprising a speed rate of zero miles per hour or receiving an indication of a desired change in vehicle acceleration.
 15. A method comprising: determining, by a controller, that a vehicle speed of a vehicle is at or above a predetermined speed limit; activating, by the controller, a motor speed governor responsive to an input received by the controller, wherein the motor speed governor is structured to control the vehicle speed; and adjusting, by the controller via the motor speed governor, an output torque based on the vehicle speed being at or above the predetermined speed limit.
 16. The method of claim 15, wherein the motor speed governor is operable between a first speed and a second speed, and wherein the first speed comprises a speed rate of zero miles per hour and the second speed comprises a calibratable speed.
 17. The method of claim 15, further comprising deactivating, by the controller, the motor speed governor responsive to at least one of the vehicle speed comprising a speed rate of zero miles per hour or receiving an indication of the vehicle speed being below the predetermined speed limit.
 18. The method of claim 16, further comprising monitoring, by the controller, the vehicle speed.
 19. The method of claim 18, further comprising providing, by controller, an indication of a change in vehicle speed to the motor speed governor.
 20. The method of claim 16, further comprising, reducing, by the controller, the vehicle speed by causing a motor to initiate a power generating state. 